When shopping for an air compressor, there’re two major options you’ll have to choose from. Oil lubricated compressors and oil-free compressors.
Though both perform the same function of compressing air, they are very different from each other in the way they work, makeup, and the type of application they’re designed for.
That is why it is very important that you know the difference between the two before spending a dime on any one.
In this article, we’re going to explain the differences between the two types, so you can choose the right one for your application.
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What Are The Differences?
An air compressor is made up of 3 major parts, an electric motor or gas engine that provides mechanical power, a pump that draws in atmospheric air and compresses it, and a storage tank for the compressed air to flow into.
Talking about oil and oil-free compressors, we’re talking about the means of lubrication of the pump in the machine.
To compress air, the pump draws in air from the atmosphere with the aid of a piston or rotary screw in a chamber, where the air is further compressed by the reciprocating action of the piston, and the compressed air is finally discharged into the storage tank.
For the pump to work properly, the piston or rotary screw needs to move smoothly within its housing with the least amount of resistance or friction. To achieve that, it needs to be lubricated properly.
Oil air compressors makes use of oil for the lubrication. This means you have to add in oil and change the oil on a regular basis for the machine to continue functioning, just the way you change the oil of your gasoline generator or car.
On the other hand, oil-free air compressors does not need to be lubricated with oil. You don’t have to change any oil once you start using it.
To get around this, the pump mechanism like the piston and housing are coated with materials such as Teflon. It does not make use of oil at all.
Some oil-free pumps also use water in place of oil as the lubrication material and also for cooling the pump during operation.
Most manufacturers also use low horsepower and low RPM motors for running oil-free pumps to reduce wear, tear and noise produced while operating the machine.
Pros and Cons of an Oiled Compressor Vs Oil-free
Both type of machines have their own advantages and disadvantages. So, let explore them.
One major difference between oil compressors and oil-free compressors is in their noise production. Oil units are less noisy than oil-free units.
This is because the oil lubricated units are well lubricated than the oil-free ones. Hence, they run more quietly because there’s less friction between the moving parts of the pump.
So, if a noisy unit is going to pose some challenges for you, then you’d want to consider going for an oil lubricated unit. On the other hand, if you don’t care about the noise produced by the machine, then you can go for any of them.
Between an oil lubricated unit and an oil-free one, the oil lubricated air compressors require more maintenance than oil-free air compressors.
Just like the oil in your car, the oil in the oil lubricated unit will eventually go bad and will need replacement. That means you have to remove it and replace it with new oil.
You’ll need to carry on continuous routine maintenance when using a compressor with an oil-lubricated pump.
On the other hand, the oil-free units come with permanent lubrication and does not need to be lubricated again throughout the life of the machine. That’s why they require less maintenance.
One of the major issue that arises when making use of oil lubricated air compressors is that the compressed air gets contaminated with the oil.
Depending on what you’re using the compressed air for, this can be very detrimental to the equipment or tools you’re powering with it and the projects you’re working on, or it may not affect anything at all.
For instance, if you run a company or workshop where a little bit of oil contamination in the compressed air will not be a huge problem, like an automobile workshop, then making use of an oil-lubed machine is fine.
You can run your air tools like air hammers, impact wrenches, sanders, sandblasters and ratchets with oil-lubed units without any problem.
On the other hand, if you run a company where any contamination no matter how minute it is, is a serious issue, then going for an oil free machine is the ideal thing to do.
For instance, high purity air is needed when you operate machines that process foods, medicine, electronics and other highly sensitive products.
Using oil contaminated air for tools like a paint prayer might also contaminate the paint with the oil, making it harder for the paint to dry or have a good finish.
You can use air filters and separators to remove the oil from the compressed air before passing it along to your tools and equipment, but if you really want no spec of oil in your system, going for an oil-free unit is the ideal thing to do.
Durability is another important issue when it comes to oil-lubed and oil-free air compressors. Oil-lube units are obviously more durable than oil-free units, because with oil in the pump and less friction taking place, there’s not much wear and tear going on in the machine.
If the oil in the machine gets bad, all you have to do is replace it with a new one and you’re running like new again.
On the other hand, the permanent lubrication with materials like Teflon of oil-free units do wear out over time. Once it wears out, the machine gets louder and louder making more noise, until it eventually falls apart.
That’s why oil-lubed units are more durable and are used for commercial projects that require long working hours. They’re more durable because there’s constant lubrication to reduce friction and cool down the machine.
Oil-lubricated units are usually more expensive than oil-less machines because there’re more working parts in the oil lubricated units.
So, if you’re a homeowner who needs an air compressor machine for simple DIY projects at home like filling mattresses, car and bicycle tires, then a small oil-free unit is the way to go because it’s cheaper and easier to maintain.
On the other hand, if you need one for industrial projects like powering pneumatic tools in your dealership or automobile workshop, then going for a heavy duty oil-lubricated one is the better option, based on the amount of usage you hope to get out of the machine.
In this case, size is usually the deciding factor rather tan cost. So, consider the pros and the cons of an oiled unit vs an oil-free unit, and choose the best one that suits your needs.